Semiconductor light-emitting devices, such as light emitting diodes (LED), are formed by using semiconductor materials. The semiconductor light emitting devices are one kind of minute solid-state light sources that can transform electrical energy into light energy. The semiconductor light emitting devices are not only small in volume, use a low driving voltage, rapid in response speed, shockproof, and long-lived, but also can meet the lightness, thinness, and miniaturization needs of various apparatuses, and thus have been widely applied in various electric products in daily life.
Currently, a very common method for increasing the light output of light-emitting diode devices is to increase the light extraction efficiency of the light-emitting diodes. The methods for increasing the light extraction efficiency of light-emitting diodes substantially includes several methods described as following. The first method is to roughen the surface of the light-emitting diode by directly etching the surface of the light-emitting diode, so as to achieve the effect of increasing the light extraction efficiency of the light-emitting diode. In the method of roughening the surface of the light-emitting diode, a local region of the surface is usually protected by a mask, and wet etching or dry etching us performed to achieve the effect of roughening the surface. However, in this conventional method for roughening the surface, the uniformity of the roughening surface is poor. The second method is to change the figure of the light-emitting diode by etching. The third method is to set a reflection mirror. However, the processes of the second method and the third method are more complicated, so that the process yield is poor.
Therefore, the conventional techniques of increasing the light extraction of the light-emitting diode are not desirable.